Composting is a process which generally provides two major benefits. It provides a method for handling organic waste materials so that these materials need not be disposed of in landfills, incinerators or in other non-environmentally beneficial disposal facilities. Furthermore, composting produces end materials, also known as the finished compost, which is highly regarded for its ability to improve soils and enhance plant growth. See: E. Fabian, et al. "Agricultural Composting: A Feasibility Study for New York Farms, a Staff Report from Cornell Composting" (February, 1993).
However, most traditional methods of composting suffer considerable drawbacks. Composting in windows, piles, pits or vaults necessitates the usage of considerable time and real estate. Large machinery is then also necessary to turn the composting materials in order to aerate the materials. Compaction is yet another problem with these methods. Thorough decomposition of the compost materials requires maintenance of proper levels of moisture, heat and aeration in the mass throughout the process. Compost materials which are simply stacked in stationary windrows, piles or pits do not permit accurate maintenance of these critical conditions throughout the mass of composting materials.
There have been attempts to address these conditions in the past. For instance, several persons have proposed rotating cylindrical composting apparatuses to avoid compaction and remove the need for large machinery to turn the composting material. See e.g., Carlsson et al. (U.S. Pat. No. 2,954,285); Shibayama et al. (U.S. Pat. No. 3,676,074); Eweson (U.S. Pat. No. 3,930,799); Kreuzburg et al. (U.S. Pat. No. 4,204,959); and Murphy et al. (U.S. Pat. No. 5,169,782); among others.
Moreover, the movement of rotatable cutting and scraping elements through composting material to agitate these materials and keep them from compacting have also been attempted. See e.g., Brown (U.S. Pat. No. 3,556,420); Waldenville (U.S. Pat. No. 3,845,939); Robbins (U.S. Pat. No. 3,850,364) and Brill (U.S. Pat. No. 4,411,682). However, in each of these examples the cutters and scrapers are fixed to a rotating shaft mounted within a stationary cylindrical drum.
Furthermore, some of those previous composting apparatuses which have had rotating drums as parts of their assemblies have also taught the affixation of various elements to the interior surfaces of the rotating drums for the purpose of, inter alia, agitating and lifting and moving the mass of composing materials along the length of the rotating drum. For example, Murphy, ibid, disclosed longitudinal vanes; Shibayama, ibid, taught lifting cross pieces and Kreuzburg, ibid, taught partition walls. Also, Eweson taught the attachment of knives and chains to the interior surface of a rotating drum to cut, shred, crush and grind composting materials moving therethrough.
Still further, limited computerized composting controls have been introduced in Waldenville, ibid, Blackwood et al. (U.S. Pat. No. 5,049,486) and C. Eccles et al., "Controlled Composting, Microcomputers Monitor Static Pile Performance," BioCycle (January 1987). These have all three been generally directed to time and/or temperature measurements and control of non-rotating drum composting environments.
However, even in view of these prior apparatuses, there remains a need for a composting apparatus which provides satisfactory control over the amounts of aeration, moisture and heat present throughout a mass of moving composting materials. It is toward the satisfaction of this need that the present invention is directed.